Apparatus for the production of 1,2-dihydroquinolines

ABSTRACT

THROUGH, A SECOND REACTOR BEING A PACKED TOWER OF LESSER HEIGHT, THROUGH WHICH THE PARTIALLY REACTED MIXTURE DESCENDS AN EVAPORATOR TO EVAPORATE THE UNREACTED AROMATIC AMINE FROM THE SUBSTITUTED 1,2-DIHYDROQUINOLINE OBTAINED, AND MEANS FOR STRIPPING THE LIGHT FRACTIONS EVOLVED IN THE FIRST REACTOR AND IN THE EVAPORATOR AND REUSING THE SAME AS STARTING MATERIALS.   NOVEL SUBSTITUTED 1,2-DIHYDROQUINOLINES HAVE ANTIOXIDANT, BACTERICIDAL AND FUNGICIDAL PROPERTIES. SAID 1,2DIHYDROQUINOLINES ARE PREPARED BY CONDENSING, IN THE PRESENCE OF A CATALYST, PREFERABLY IODINE, A SUBSTITUTED AROMATIC AMINE WITH A CARBONYL COMPOUND, AT A TEMPERATURE OF BETWEEN 90 TO 300*C., SAID CATALYST BEING PREFERABLY PRESENT TOGETHER WITH AN ACTIVATOR SELECTED FROM ALKYL OR ALKARYL HALIDES. SAID PROCESS IS PREDERABLY CARRIED OUT IN AN APPARATUS ESSENTIALLY COMPRISING A MIXING AND FEEDING DEVICE, A FIRST REACTOR BEING A PACKED TOWER OF A HEIGHT SUFFICIENT TO PROVIDE FOR THE NECESSARY RESIDENCE TIME OF THE REACTION MIXTURE IN CONTINUOUS ASCENDING FLOW THERE-

Aug. 13, 1914 g. MQNROY 3,829,292

APPARATUS FOR THE PRODUCTION OF 1,2'TDIHYDROGUINOLINES Original FiledApril 26. 1971 US. .Cl. 23-263 1 Claim ABSTRACT OF THE DISCLOSURE Novelsubstituted '1,2 dihydroquinolines have antioxidant, bactericidal andfungicidal properties. Said 1,2- dihydroquinolines are prepared bycondensing, in the presence of a catalyst, preferably iodine, asubstituted aromatic amine with a carbonyl compound, at a temperature ofbetween 90 and 300 C., said catalyst being preferably present togetherwith an activator selected from alkyl or alkaryl halides. Said processis preferably carried out in an apparatus essentially comprising amixing and feeding device, a first reactor being a packed tower of aheight suflicient to provide for the necessary residence time of thereaction mixture in continuous ascending flow therethrough, a secondreactor being a packed tower of lesser height, through which thepartially reacted mixture descends an evaporator to evaporate theunreacted aromatic amine from the substituted 1,2-dihydroquinolineobtained, and means for stripping the light fractions evolved in thefirst reactor and in the evaporator and reusing the same as startingmaterials.

This is a division of application Ser. No. 137,217, tfiled Apr. 26,1971, and now abandon.

BACKGROUND OF THE INVENTION The present invention refers to new1,2-dihydroquinolines and, more particularly, it is related to newsubstituted 1,2-dihydroquinolines having excellent antioxidant,bactericidal, insecticidal and fungicidal properties, and to a novelprocess and novel apparatus for the preparation of substituted1,2-dihydroquinolines.

The dihydroquinolines in accordance with the present invention arecompounds having high antioxidant and pesticidal properties andgenerally protect various materials against alterations caused by oxygenand by the influence of insects, fungi, bacteriae and other types ofparasites.

T he dihydroquinolines in accordance with the present invention arerepresented by the following general formula wherein R is hydrogen,hydroxy, lower alkoxy, nitro or halogen; R is hydrogen, nitro, halogen,alkyl, aryl or carboxyal'kyl; R is hydrogen or alkyl; R, is alkyl oraralkyl; R is hydrogen or alkyl; and R is hydrogen, alkyl or alkaryl.

'Dihydroquinolines are highly susceptible to decoloration by the actionof the ambient oxygen. For instance, prior publications disclose1,2-dihydro 2,2,4 trimethylquinoline and 1,2-dihydro-2,2,4 trimethyl 6ethoxyquinoline as products which are considerably degradated and whichsuffer intensive decolorations with time. Trior United States Patent 03,829,292 Patented Aug. 13, 1 974 Ice publications particularly describe1,2 dihydro 2,2,4-trimethyl-6-ethoxyquinoline as a brown coloredproduct, but it is quite obvious that such a color is due to the actionof the oxygen thereon.

However, it is believed that the intensive decoloration of the prior artdihydroquinolines is mainly due to impurities present in such products,inasmuch as, upon carefully distilling the above mentioneddihydroquinolines, it found that they are then much less sensitive tothe attack by the oxygen and therefore this proves that, the purer thecompound, the less sensitive to the oxygen it is. It is quite probable,therefore, that impurities contained in the commercially availableproducts, are the main cause of decolorations, because said impuritiesfacilitate attack by the oxygen which causes a fast decoloration of saidproducts when the same have not been redistilled.

These compounds can be polymerized through the use of acidic catalystssuch as aluminum chloride, boron trifluoride or phosphoric acid in orderto produce highly efiective antioxidants for rubber and relatedpolymers.

SUMMARY OF THE INVENTION Having in mind the defects of the prior artdihydroquinolines, it is an object of the present invention to providenew substituted 1,2-dihydroquinolines having highly improvedcharacteristics against decoloration, without the need of having resortto costly purifying procedures.

-It is another object of the present invention to provide novelsubstituted 1,2-dihydroquinolines having high antioxidant, bactericidal,insecticidal and fungicidal properties.

A further object of the present invention is to provide1,2-dihydroquinolines of the above mentioned character, which will alsohave an extremely low toxicity to render them useful for theirincorporation in food products.

Another object of the present invention is to provide a novel processfor the preparation of substituted 1,2-dihydroquinol'ines, which is ofsimpler operation as well as of highly economical characteristics.

A further object of this invention is to provide a process of the abovementioned character, which will require 'a reaction period quite shorterthan conventional processes, through the use of suitable catalysts.

It is another object of the present invention to provide an apparatusfor carrying out a process of the above mentioned character in acontinuous manner to produce substituted 1,2-dihydroquinolines.

BRIE'F DES'ECRIPTION OF THE DRAWINGS The novel features that areconsidered characteristic of the present invention are set forth withparticularity in the appended claim. The invention itself, however, bothas to its organization and its method of operation, together withadditional objects and advantages thereof, will best be understood fromthe following description of a specific embodiment, when read inconnection with the accompanying drawing, in which:

The single figure is a flow sheet diagrammatically representing theprocedural steps and the preferred apparatus used to prepare substituted1,2-dihydroquinolines.

DETAILED DESCRIPTION OF THE INVENTION The process in accordance with thepresent invention comprises, broadly speaking, condensing, in thepresence of suitable catalysts, aromatic amines with aldehydes orketones containing the group COCH The condensation reaction ispreferably elfected at high temperatures, such as between and 300 C.,and for a period of time of from about 3 to about 12 hours, whichconditions are obtained by feeding a cold mixture of the amine, thecarbonyl compound and the catalyst into the bottom of a packed tower ofsufiicient height to provide for a suitable residence time of thereacting mixture, said packed tower being provided with heating means toobtain the desired reaction temperature. A mixture of the carbonylcompound and water is evolved and the carbonyl compound is recovered byfractional distillation to be dried and reused as a starting material inthe Process.

A mixture of the desired dihydroquinoline product and unreacted aromaticamine is obtained through the bottom of a secondary reactor fed from thefirst reactor by the top thereof, and said mixture is distilled torecover the aromatic amine and thus purify the 1,2-dihydroquinolineproduct.

The process for the obtention of the 1,2-dihydroquinolines according tothe present invention can be represented by the following equation:

wherein R is hydrogen, hydroxy, lower alkoxy, nitro or halogen; R ishydrogen, nitro, halogen, alkyl, aryl or carboxyalkyl; R is hydrogen oralkyl; R; is alkyl or aralkyl, R is hydrogen or alkyl; and R ishydrogen, alkyl or alkaryl.

Any aromatic amine having the above disclosed formula can be used tocarry out the process of the present invention, but highly preferablestarting compounds are aniline, p-chloroaniline and p-phenetidine forthe obtention of substituted 1,2-dihydroquinolines in accordance withthe present invention.

Any carbonyl compound represented by the formula disclosed in the aboveequation can also be used, but the folowing are preferable: Acetone,methyl ethyl ketone, methyl isobutyl ketone and butyraldehyde.

The catalysts preferred to carry out the condensation reaction whichforms the main object of the present invention are iodine,p-toluenesulfonic acid and sulfanilic acid, with iodine being thepreferred catalyst in view of the fact that it produces the highestyields and requires the shortest reaction periods. Highly preferably,the above catalysts are used in admixture with an activator selectedfrom alkyl or alkenyl halides such as ethylene dichloride,dichloroethylene, trichloroethylene and the like.

The preferred amount of catalyst used in the reaction is of from about1% to'4%, preferably about 3% by weight on the weight of the aromaticamine.

The activator is desirably added to the catalyst in an amount of from13% to 80%, preferably about 70% by weight on the weight of catalystused.

While anyone skilled in the art will clearly understand that the abovementioned process can be effected in any convenient manner such as byletting the starting mate rials interact in the presence of the catalystin a batchtype reactor, the present invention contemplates a continuousprocess which is preferably carried out in an installation of the typediagrammatically shown in the single figure of the drawings.

Having now more particular reference to the drawing, the apparatus forthe continuous manufacture of the 1,2.- dihydroquinolines of the presentinvention comprises a mixing vessel 1, a metering feed pump 2, a firstreactor 3, a fractional distillation column 4, a condenser 5, a secondreactor 6, a surge tank 25, a circulating evaporator 7, a fractionaldistillation column 8 and a condenser 9.

:Reactor 3 is a packed tower provided with external heating means suchas an oil jacket 10 or the like, with a suitable packing such as Raschigrings, stainless steel mesh rolls or the like, to provide for a largecontacting area, and the height of the column is designed such that asuitable residence time is provided to effect the condensation reaction.Reactor 6 is similar to reactor 3, being a packed tower of a shorterlength provided with external heating means such as an oil jacket 11 inorder to keep the temperature within the specified desired range.

The process in accordance with the present invention is carried out asfollows:

Suitable proportions of the aromatic amine, the carbonyl compound, thecatalyst and, if desired, the activator, are continuously fed into themixing vessel 1 wherein a homogeneous mixture of said ingredients isobtained. The metering feed pump 2 meters a controlled flow of thereaction mixture from vessel 1 into the bottom of reactor 3 through line14. The mixture is heated to the desired temperature of between about to300 C., depending on the starting materials used and on the productdesired. A mixture of the volatile carbonyl compound and Water isvaporized and distilled through the fractionating column 4, in which thehigher boiling compounds including water are recycled to reactor 3 whilethe carbonyl compound is carried through line 15 to a suitable condenser5, from which the liquid carbonyl compound is removed through line 16 tobe reused in the process.

The liquid component of the reaction mixture is discharged through theoverflow line 17 to the top of the second reactor 6 in which thereaction is completed, with the product mixed with unreacted aromaticamine being discharged through line 18.

The mixture of the dihydroquinoline, water and unreacted aromatic amineis received in a surge tank 25 from which it is discharged through line19 into a circulating convection evaporator 7 which operates in abatch-like manner.

The evaporator 7 comprises an inclined pipe bundle 12 at which lower endthe mixture of 1,2-dihydroquinoline, water and aromatic amine is fed andcirculated through the pipe 13 by means of the convection currentcreated by the pipe bundle 12. The aromatic amine, water and otherimpurities are evaporated and received in fractionating column 8 throughline 20 to be furtherly purified. The heavier fraction consisting of the1,2-dihydroquinoline entrained in the vapors is removed from the bottomof column 8 through line 24, either to be recycled to the evaporator,through line 26, or to be removed as the final product, through line 27,while the lighter fraction comprising aromatic amine, water and otherimpurities is vaporized through line 21 and furtherly condensed incondenser 9, whence it is discharged in liquid form through line 22 tobe rectified or else reused in the process. The desired product can alsobe discharged through line 23 from evaporator 7 at suitable intervals.

It will be thus seen that the process for the production of1,2-dihydroquinolines eifected in the apparatus in accordance with thepresent invention may be considered as a continuous process having aremarkable efliciency and comprising a reaction period of not more thana small fraction of the period of time necessary in a conventionalreactor. Also, the design of the continuous reactor of the presentinvention avoids undue polymerization and resinification of the productformed, in view of the fact that the reaction mixture is subjected tohigh temperatures only a relatively short time.

The present invention will best be understood by the followingillustrative examples, which must be construed as merely illustrativeand not restrictive of the true scope of the invention.

EXAMPLE 1 Preparation of 1,2-dihydro-2,2,4-trimethylquinoline 35 g. ofmetallic iodine, 24 g. of trichloroethylene and 2040 g. of aniline arejointly dissolved in 4020 g. of acetone and the mixture is pumped toreactor 3 of the accompanying drawing at a rate of flow suitable toprovide a residence time of about 3.5 hours. The jackets of the 5.reactors arefed with heating oil to raise the temperature of thereactionmixture to about 160 C.

I -A mixture of water, acetone and aniline is fed to column 4 andpractically ,pure acetone is removed in the form of vapors to becondensed in condenser whence the acetone is recirculated to theprocess. I

The mixture of unreacted aniline and the produc obtained is received inthe surgetank 25 and the evaporated and rectified in order to purify theproduct and remove water and the aniline, to be reused in the process.

The reaction effected in accordance with this example can be representedby the following equation:

The 1,2-dihydro-2,2,4-trimethylquinoline obtained is a brown coloredproduct having a refractive index at 23 C. of 1.582, a boiling point at0.1 mm. of mercury of 94 to 96 C. and a specific gravity at 22 C. of0.9430. The conversion rate per pass calculated on the aniline feed wasapproximately 45%.

7 The product obtained is an antioxidant having parasiticide properties,which can bepolymerized' to enhance its stability and activity.

EXAMPLE 2 I I Preparation of 1,2-dihydro-2,3,4-trimethy1-2-ethylquinoline In the same manner described in Example 1, 40 g. ofiodine, 28 g. of ethylene dichloride, 2040 g. of aniline and 5000 g. ofmethyl ethyl ketone are reacted at a temperature of 185 C. for a periodof about 5 hours and 40 minutes.

The 1,2-dihydro-2,3,4-trimethyl-2-ethylquinoline thus obtained is ayellow liquid having a refractive index at 24 C. of 1.571,. a boilingpoint at 0.1 mm. of mercury of 110 to 112 C. and a specific gravity at23.5 C. of 0.9712. Theconversion rate per pass calculated on the anilinefeed is about: 37%.

The product'obtained is an excellent antioxidant having remarkableparasiticide properties.

EXAMPLE 3 Preparation of 1,2-dihydro-2,2,4-trimethyl- I "6-ethoxyquinoline 7 NH CHI I Y 1 +2C=O 011150 (3H3 C2H5O 45 g. of metalliciodine, 9 g. of trichloroethylene, 3000 g. of p-phenetidine and 4020 g.of acetone are reacted in the same manner described in Example 1 at atemperature of about 205 C. and ata-rate of flow suitable to provide fora residence time of about 4 hours and 40 minutes.

- The l,2-dihydro-2,2,4-trimethyl-6-ethoxyquinoline obtained was a lightyellow to amber colored liquid having a refractive index at 20 C. of1.568, a boiling point at 0.1 mm. of mercury of 134 to 136 C. and aspecific gravity at 21 C. of 1.031. The conversion rate per passcalculated on the p-phenitidine was about 40%.

The product obtained proved to be an excellent antioxidant havingremarkable insecticide, fungicide and bactericide properties, which canbe polymerized to enhance its stability and activity.

EXAMPLE 4 Preparation of 1,2-dihydro-2,3,4-trimethyl-2-ethyl-6-ethoxyquinoline NH, C2H5 2 =0 C2H5O H3 CH, +2H,0 CzHsO H3 Inthe same manner described in Example 1, 30 g. of iodine, 21 g. ofdichloroethylene, 200 g. of p-phenetidine and 3500 g. of methyl ethylketone are reacted at a temperature of about 220 C. and for a period ofabout 5 hours and 20 minutes.

The 1,2 dihydro 2,3,4 trimethy1-2-ethyl-6-ethoxyquinoline obtained was ayellow to light amber colored liquid having a refractive index at 23 C.of 1.560, a boiling point at 0.1 mm. of mercury of 139 to 141 C. and aspecific gravity at 232 C. of 0.9858. The conversion rate per passcalculated on the p-phenetidine was of about 38.5%.

The product obtained produced excellent results as an antioxidant andpossessed good parasiticide properties.

EXAMPLE 5 Preparation of 1,2-dihydro-2-n-propyl-3-ethylquinoline H 21120CzHs 40 g. of sulphanilic acid, 2040 g. of aniline and 5000 g. ofn-butyraldehyde are reacted in the same manner described in Example 1,at a temperature of about 180 C. for a period of about 10 hours.

In this particular case iodine and unreacted n-butyraldehyde and anilineare not separately obtained but, on the contrary, the aniline completelyreacts forming three different products. The first product is the Schifibase formed between the aniline and the butyraldehyde, represented bythe formula having a boiling point at 0.1 mm. of mercury of 98 to C. Thesecond product is the desired 1,2-dihydro- 2-n-propyl-3-ethylquinolineand the third product is a resinous soft residue probably comprising apolymeriza tion product of the substituted dihydroquinoline due to therather long reaction period necessary in this particular case.

The desired product is purified by decantation of the solid residue inthe surge tank 25 and is then evaporated and fractionally distilled inorder to separate it from the Schifl base, with the latter being reusedto continue the reaction for additionally forming the substituteddihydroquinoline.

The l,2-dihydro-2-n-propyl3-ethylquinoline obtained was a light lemongreen colored liquid having a refractive index at 23 C. of 1.570, aboiling point at 0.1 mm. of mercury of to 122 C.,'and a specific gravityat 22.5 C. of 0.9776. The conversion rate per pass calculated on theaniline feed was about 35%.

The product obtained was an excellent antioxidant having very goodparasiticide properties.

EXAMPLE 6 Preparation of l,2-dihydro-2-n-propyl-3-ethyl-6-ethoxyquinoline NHz 2C H7CH=O CzHsO In the same manner described inExample 5, a mixture of 30 g. of p-toluene sulfonic acid, 2000 g. ofp-phenetidine and 4400 g. of n-butyraldehyde is reacted at a temperatureof about 220 C. and for a period of 4 hours and minutes.

In this particular case the Schiif base of the p-phenetidine andbutyraldehyde is also obtained having the formula with a boiling pointat 0.1 mm. of mercury of 140 to 145 C. Also, of course, the desired1,2-dihydro-2-npropyl-3-ethyl-6-ethoxyquinoline is formed.

The desired product is fractionally distilled under vacuum in order topurify it and remove the Schiff base, the latter being recirculated tothe reaction to additionally form the desired dihydroquinoline.

The 1,2-dihydro-2-n-propyl-3-ethyl-fi-ethoxyquinoline obtained was alight lemon green colored liquid with a refractive index at C. of 1.559,a boiling point at 0.1 mm. of mercury of 154 to 158 C. and a specificgravity at 22.7 C. of 1.0006. The yield on the p-phenetidine feed wasabout 33%.

The product obtained was an excellent antioxidant with very goodparasiticide properties.

EXAMPLE 7 Preparation of 1,2-dihydro-2,2,4-trimethyl-6- chloroquinolineH CH OH: NH: a /N\ 21120 2(IJ=O CH3 (:1 CH; 01

EXAMPLE 8 Preparation of 1,2-dihydro-2,3,4-trimethyl-2-ethy1-6-chloroquinoline C1 -CH3 NHI 02115 lHa In the same manner described inExample 1, a. mix-' ture of 22 moles of p-chloroaniline, 70 moles ofmethyl ethyl ketone, 2% of iodine and 1.4% of trichloroethylene werereacted at a temperature of about 180 Crfor a" Preparation of1,2-dihydro-2,2,4-trimethyl-8 nitroquinoline N0: OH: 211.0 2(|J=O om CHaI V a NHg In the same manner described in Example 1 a mix ture of 22moles of o-nitroaniline, 70 moles of acetone with 2% of p-toluenesulfonic acid and 1.4% of ethyl ene dichloride was reacted at atemperature of about 180 C. for a period of about 4.5 hours.

The 1,2-dihydro-2,2,4-trimethyl-S-nitroquinoline ob-- tained was anamber colored solid with a melting point of about 60 C. and a boilingpoint at 0.1 mm. of mercury of about 150 C.

The product obtained was a good antioxidant having parasiticideproperties.

EXAMPLE 10 Preparation of 1,2-dihydro-2,4-dimethyl-2-isobutyl3-isopropylquinoline CHa-C H-CH: NHfl 11 CH3 CH8 In the same mannerdescribed in Example 1, a mixture of 22 moles of aniline, 70 moles ofmethyl isobutyl ketone, 2% of metallic iodine and 1.4% of ethylenedichloride was reacted at a temperature of 180 C. for a period of about6 hours.

The 1,2-dihydro-2,4-dimethyl 2 isobutyl-3-isopropylquinoline obtainedwas an orange yellowish colored liquid having a refractive index at 23C. of 1.550, a boiling point at 0.1 mm. of mercury of to C. and aspecific gravity at 19 C. of 0.9063.

The product obtained was an excellent antioxidant with very goodparasiticide properties.

From the above it will be clearly seen that a highly improved andeflicient process has been provided for the obtention of substituted1,2-dihydroquinolines having excellent antioxidant properties and alsobeing very good fungicides, insecticides and bactericides. Also, a novelapparatus to carry out the above described process has been provided, inwhich the continuous efiicient production of the substituted1,2-dihydroquinolines of the present in vention can be etfected withincreased efliciency and reduced reaction times, thus producing veryhigh quality compounds.

What is claimed is:

1. An apparatus for the continuous production of substituted1,2-dihydroquinolines by the reaction of an aromatic amine with thecorresponding substituted carbonyl compound in the presence of acatalyst, said apparatus comprising:

(1) a first reactor consisting of a tower having a packed extendedsurface therein and means associated therewith to heat said tower andhaving a height sufficient to provide the necessary residence time forthe reaction mixture ascending therethrough;

(2) means for mixing and feeding the reactants and catalyst to thebottom portion of said first reactor whereby said reactants flowupwardly therethrough producing a reaction mixture comprised of a liquidand a vapor portion;

(3) a second reactor consisting of a tower having a packed extendedsurface therein and means associated therewith to heat said tower andhaving a height less than the height of said first reactor;

(4) means to remove the liquid portion of said reaction mixture from thetop portion of said first reactor and I feed said liquid portion to thetop of said second reactor whereby said liquid portion descendstherethrough and said reaction is completed thereby producing a firstliquid mixture containing the substituted product and unreacted aromaticamine;

(5) first distillation means for distilling the vapor portion of saidreaction mixture;

(6) means to feed said vapor portion of said reaction mixture from saidfirst reactor to said first distillation means whereby a firstdistillation is conducted producing a first heavy liquid fraction whichis recycled to the top portion of said first reactor as reflux and afirst light vapor fraction comprising unreacted carbonyl compound;

(7) a first condenser means for condensing said first light vaporfraction and means to feed said first light vapor fraction from saidfirst distillation means to said first condenser means, said firstcondenser means being provided with a first recycle means to recycle thecondensed first light vapor fraction to said mixing and feeding means(2);

(8) a surge tank and means to feed said first liquid mixture from thebottom portion of said second reactor to said surge tank means;

(9) evaporator means for separating the substituted product from theunreacted aromatic amine in said first liquid mixture and pumping meansfor pumping said first liquid mixture from said surge tank means to saidevaporator means, said evaporator means comprising a circulatingconvection evaporator and being provided with means for dischargingliquid substituted product therefrom, the evaporation occurring thereinproducing a second vapor stream containing unreacted aromatic amine andsubstituted product;

(10) second distillation means for distilling said second vapor streamand means to feed said second vapor stream from said evaporator means tosaid second distillation means, whereby a second distillation isconducted producing a second heavy liquid fraction comprisingsubstituted product and a second light vapor fraction comprisingunreacted aromatic amine, said second distillation means being providedwith a liquid substituted product discharge means and a second recyclemeans to recycle liquid substituted product to said evaporator means;and

(11) a second condenser means for condensing said second light vaporfraction and means to feed said second light vapor fraction from. saidsecond distillation means to said second condenser means, said secondcondenser means being provided with a third recycle means to recycle thecondensed second light vapor fraction to said mixing and feeding means(2).

References Cited UNITED STATES PATENTS 3,322,770 5/1967 DAlessandro etal. 260-283 R OTHER REFERENCES Hydrocarbon Processing, vol. 43, No. 9,September 1964, pp. 144, 147 and 176 relied on.

BARRY S. RICHMAN, Primary Examiner US. Cl. X.R.

